Pest control smoke generating devices



Oct. 11, 1955 c. H. L.u Y ETAL PEST CONTROL SMOKE GENERATING DEVICESFiled Aug. 6, 1951 /n ve nors:

United States Patent O 2,720,012 PEST CONTROL SMOKE GENERATING DEVICESCecil H. Lilly, Saltcoats, and Douglas J. B. Marke, West Kilbride,Scotland, assignors to Imperial Chemical Industries Limited, acorporation of` Great Britain Application Augusta,19s1,se1ia1Nd.z4o,s`94 Claims priority, application Great Britain August22, 1950 4 Claims. (o1. z1111) The present invention relates to pestcontrol smoke generating devices.

In British specication No. 590,293, corresponding to U. S. Patent No.2,488,776, there is described and claimed inter alia a safety fuse cordwherein one or more of the textile yarn coverings around the powder coreare coated or impregnated with a thermally vapourisable pesticidalcompound.

1n British specification No. 631,487, corresponding to U. S. Patent No.2,521,942, there is described and claimed inter alia a device forproducing an ejecting material in vapour form comprising a closedcontainer having a plurality of venting perforations in the top wallmember thereof guarded by barrier elements hindering the escape of solidparticles and sparks and spaced from the supporting wall, containing alength of combustible cord of cross section greater than that of any ofthe venting perforations impregnated with the material to be vapourisedand comprising a self-combustible material as its thermally activeconstituent, arranged in a coil below the unperforated portion of thetop wall member, one end of the cord protruding from the container forthe ignition of the said coil from the exterior, through a hole ofcorresponding cross section, so made to prevent the protruding end ofthe cord from falling back into the container. It is stated that thisdevice is particularly useful in connection with devices of the naturedescribed and claimed in British specification No. 631,113,corresponding to U. S. Patent No, 2,521,941.

The object of the present invention is to provide a pest control smokegenerating device which is safe to handle and to use for the generationof pesticidal vapours which are extremely toxic to human beings, andwhich is so constructed as to be particularly suitable for insertioninto narrow diametered holes or orifices, as for instance for droppingthrough a long hollow rod previously inserted into the heart of a nestof a leaf-cutting ant, e. g. Atta cephalotes L., Atta sexdens L.,Acromyrmax octospinoss Reich.

According to the present invention a pest control smoke generatingdevice comprises an impermeable tubular casing closed at one end andprovided at the other end with a removable cover and a length of fuse,preferably semi fuse, preferably sealed at one end and preferablyprovided at its other end with a matchhead composition, wherein the fuseif sealed at one end is enclosed in the casing with its sealed endnearer the closed end of the casing, wherein said tubular casing ispreferably provided at its open end with an ignition delay element, andwherein the said fuse has at least some of its textile yarn coveringsimpregnated with a thermally vapourisable pesticidal compound.

The impermeable tubular casing and its removable cover are preferablymade of metal as for example aluminium.

The length of fuse is preferably sealed at the end near the closed endof the casing to prevent its ejection from the casing after it isignited. It is often important to prevent the ejection of the fuselength particularly when the device is used for example in green-houses,because in this way any poisonous residual pesticide is retained withinthe impermeable tube. Instead however of sealing the fuse at one end oradditionally thereto the fuse can be retained in position on ignition bycrimping the container at one or more positions so as to grip it.

The matchhead composition facilitates` the ignition of the length offuse from the ignited ignition delay element. The latter is preferablyof such compositions as to be readily ignited by an ordinary match whichdoes not easily ignite directly a fuse or semi-fuse.

The thermally vapourisable pesticidal compound can be for example thevery powerful liquid pesticide Parathion (E605) which is OO diethylO-p-nitrophenyl thiophosphate; or for example the solid pesticide thegamma isomer of benzene hexachloride.

The invention is illustrated with reference to the diagrammatic drawingaccompanying the specification which drawing is a vertical cross sectionof a pest control smoke generating device in accordance with anembodiment of the invention. In the drawing 1 is a metal tube 5 in. inlength and 1A in. in diameter, 2 is the core of a semi- :safety fuse thetextile coverings 3 and 4 of which are impregnated with 0.3 gramParathion, 5 is the end of the semi safety fuse sealed with wax, 6 isthe end of the semi safety fuse which has been dipped in an igniter wickdope consisting of sulphurless meal 38 parts and nitrocellulose dope 57parts. 7 is a slow burning delay primer composition consisting ofammonium nitrate 40%, arnmonium dichromate 35% and nitrocellulose dope25%. 8 is a metal closure.

After removing the cover 8 the slow burning delay element 7 can beignited with an ordinary match and the tube 1 with its contents, 2, 3,4, 5, 6 and 7 inserted for instance into the hole of an ants nest ordropped through a long hollow rod previously inserted into the heart ofa nest of a leaf-cutting ant. As there is` a delay in the pick-up of theflame from the ignited delay element 7 by the core 2 of the semi-fusethere is no spit or llame to hurt the operator and no release ofinsecticide too soon before the metal tube 1, with its contents 2, 3, 4,5, 6 and 7, is in position.

In the foregoing disclosure the word fuse encompasses any elongatedmaterial that burns at a regular controllable speed. It is a genericterm to cover safety fuse, detonating fuse and a lead fuse having anincendiary composition inside it.

Safety fuse is a fuse for blasting which burns, does not explode anddoes not contain its own means of ignition. It is of such strength andconstruction and contains a burning composition in such quantity thatthe combustion of the fuse will not communicate laterally with otherlike fuses.

A semi-fuse, if of the good variety, may be a "safety fuse because sucha fuse again must not communicate its burning laterally to other likefuses. The difference between a semi-fuse and a safety fuse is that theformer does not possess any waterproof coatings and, therefore, must notcome in contact with moisture or Water.

What we claim is:

1. A pest control smoke generating device comprising a narrow,elongated, impermeable, tubular, metal casing closed at one end andprovided at the other end with a removable metal cover and an ignitiondelay element comprising a slow-burning delay primer composition, saidtubular metal casing having positioned and enclosed therein an elongatedlength of textile covered semi-fuse having at least some of its textileyarn coverings impregnated with a thermally-vaporizable pesticidalcompound 3 and said semi-fuse being iixed to the closed end of saidcasing to thereby prevent the ejection of said fuse upon ignitionthereof.

2. A pest control smoke generating device as claimed in claim 1 whereinthe metal is aluminium.

3. A pest control smoke generating device'as claimed in claim 1 whereinthe pesticidal compound is Parathion.

4. A pest control smoke generating device as claimed in claim 1 whereinthe delay primer composition comprises ammonium nitrate, ammoniumdi-chromate and nitrocellulose dope.

Fouke Jan. 30, 1923 Weinberg July 6,1926

2,090,297 Knoche Aug. 17, 1937 2,127,975 Kemp Aug. 23,1938 2,440,082Flanders Apr. 20,1948 2,488,776 Jones Nov. 22, 1949 5 2,521,941 PearsallSept. 12, 1950 2,521,942 Pearsall Sept. 12,1950 2,551,406 Yent May 1,1951 2,603,607 Stevenson July 15, 1952 OTHER REFERENCES Gersdorf, W. A.,et a1., in Journal of Economic entomology, vol. 44, No. 4, pp. 474-6.

Pearsall, D. E., et al., Insecticidal Cords in Soap and SanitaryChemicals for October 1946, pp. 139-43, 15 161-63.

1. A PEST CONTROL SMOKE GENERATING DEVICE COMPRISING A NARROW,ELONGATED, IMPERMEABLE, TUBULAR, METAL CASING CLOSED AT ONE END ANDPROVIDED AT THE OTHER END WITH A REMOVABLE METAL COVER AND AN IGNITIONDELAY ELEMENT COMPRISING A SLOW-BURNING DELAY PRIMER COMPOSITION, SAIDTUBULAR METAL CASING HAVING POSITIONED AND ENCLOSED THEREIN AN ELONGATEDLENGTH OF TEXTILE COVERED SEMI-FUSE